JPS5914245A - Ceramic luminous tube for high pressure discharge lamp - Google Patents

Abstract

PURPOSE:To maintain the coolest point of a lamp more stably and reduce the variance of the lamp voltage and color tone by providing an expanded inner wall surface having a limited angle against the axial direction of a discharging electrode from the inner edge of the seal hole of the discharging electrode. CONSTITUTION:An expanded inner wall surface 6 having an angle theta1 of 60 deg.- 90 deg. against the axial direction of the electrode, i.e., the axial direction of a ceramic luminous tube from the inner edge of a seal hole 5 is formed. In addition, an expanded inner wall surface 7 having an angle theta2 smaller than the angle theta1 is formed between the expanded inner wall surface 6 and a luminous inner wall surface 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic arc tube for high pressure gas discharge lamps such as high pressure sodium radiation resistant and metal halide discharge lamps.

In recent years, high-pressure sodium discharge lamps and metal halide discharge lamps have been put out of practical use due to their excellent lighting efficiency, and numerous improvements have been made to improve efficiency and color rendering, including the use of ceramic six-light tubes. As shown in FIG. 1, a ceramic arc tube 1 has been proposed in which both ends 2 of an arc tube are smaller than the outer shape of the central portion of the arc tube (Japanese Utility Model Application No. 56-12TI761).

This J-shaped ceramic arc tube requires a small number of parts and assembly work when installed in a lamp. r<The placed he is crushed because it can reduce costs and there is less heat emitted from the ends, but when assembled into two lamps, the C junction near the release electrodes at both ends, that is, the discharge light emission. Material analogy,
The following week, the sodium reservoir H'' was unstable, causing fluctuations in lamp voltage and lamp color θ1°d.

The reason for this is thought to be that the coldest point depends on the distance hbt between the arrival holes 8 at both ends into which the intoxication electrodes are inserted and on the thermal balance at the tube ends.

That is, the above I distance is determined by the dimensional accuracy of the sealing hole diameter and the dimensional accuracy of the inner wall surface of the arc tube near the sealing hole diameter.
be. The dimensional accuracy of the sealing hole diameter is equivalent to W pole's airtight sealing stone, so the manufacturing method for ceramic arc tubes is to mold the sealing hole smaller than the specified diameter and then finish it with mechanical processing to obtain the specified dimensions. . The reason why machining the diameter of the sealing hole is safe is because the inner bag surface of the ceramic optical tube is mainly formed by blowing molding, so the diameter of the sealing hole is not constant.

Regarding the thermal balance at the end of the tube, it is thought that although it is possible to reduce the heat flux by making the outer diameter of the tube end smaller than that of the entire light emitting section, the thermal equilibrium is unstable due to variations in the shape of the inner wall surface. It will be done.

The present invention has been made in order to eliminate such drawbacks, and the present invention has been made in such a way that the outer diameter of the tube end where the discharge electrode is provided is smaller than the outer diameter of the tube center portion of the light emitting section, and the tube end portion and the tube center portion are integrated with ceramic. High pressure M iH, El 144 made of material
The ceramic light tube has an enlarged diameter inner wall surface having an angle of 60° to 90° from the inner end of the sealing hole of the discharge electrode with respect to the axial direction of the discharge FL pole, and This ceramic helmet for a high pressure discharge lamp has an enlarged diameter inner wall 1 smaller than the above angle between the enlarged diameter inner wall surface and the light emitting inner wall 1 at the center of the tube.

The details of the invention will be explained with reference to Eko.

As shown in FIG. 2, a ceramic arc tube for pressure discharge ablation (hereinafter referred to as ceramic arc tube: 1i4-) 4 according to the present invention has a discharge electrode (hereinafter referred to as ``fue'' or ``oki'') or a sealed material. The outer shape of the fleshy end portion having the hole 6 is smaller than the outer shape of the central portion of the tube that emits light, and the luminescent ceramic material, for example, is made of alumina, and is formed seamlessly and integrally. From the inner end of the sealing hole 5 in the axial direction of the m pole, that is, the ceramic h yt, w
An angle of 60° to 90° (0□) with respect to the direction of the axis of
An enlarged diameter inner wall...16 is formed. The reason for limiting to such an angle is that in high-pressure discharge, the lamp voltage is usually specified as lOυ~20°V±lθ%, and for this purpose, the distance between the inner fields of the sealing holes 5 where the electrodes are sealed is 1Mt. The dimensional error is within ±2% of the material, and is usually within 8-2.
When forming four sealing holes 5, the angle must be 60° or more to keep within the above error, and if the angle is 90' or more, four parts will be formed on the lamp inner wall m1, and the coldest point will be This is because it receives 1 so.

There is an angle I between the enlarged diameter inner wall surface 6 and the optical part inner wall direction 8.
An enlarged diameter inner wall having an angle (θ2) smaller than W (0□)...
17 are formed. The reason for limiting the angle to such an angle is that if the arc tube is formed by the enlarged diameter inner wall surface 6 and the osseous blood 8 in the light emitting part at the above angle (θ□), the outer shape of the end of the tube will not be the same as that of the light emitting part. The effect of making it smaller than the external shape is not enough, and the shape change from the end of the tube to the light emitting part is large, so the molding of the ceramic is difficult, and even if it is completed, distortion will remain. This is because the heat magic attack when the lamp flashes will cause destruction. The length of each 6.7 degrees in the inward direction of the enlarged diameter may vary depending on the characteristics of the lamp. .

Further, an inner wall surface 8 parallel to the axial direction of the m-pole may be provided between the enlarged-diameter inner wall surface 6 and the enlarged-diameter inner wall surface 7, as shown in FIG. By providing such an inner wall surface 8, the coldest spot can be kept more constant, and therefore a shape suitable for providing a heat insulating plate on the outer periphery is provided.

The dilated internal condyle I7 having an angle (0,) is not limited to the conical shape of the second meat, but may be shaped like a curved surface as shown in FIG. 8. Also, as shown in Figure 8, the thickness of the tube at the center of the tube (t
l) is made thin to maintain the amount of light transmitted through the lamp by h, and the rtM-wall thickness (1,) at the end of the tube is the sealing S of the discharge electrode.
It is also effective that the lamp is large enough to withstand the heat 11i and the force when the lamp flashes.

Example 9 After thoroughly mixing 0.1gfi% of electrified magnesium powder, 4% of methylcellulose, and 1% of polyethylene oxide with 9.95% high-purity alumina fine powder wood, 20% of water was added thereto and mixed with a kneader. #Js.

After mixing, the clay material is put into a vacuum kneading machine and kneaded while being vacuumed to produce a clay material for extrusion molding with an outer diameter of 40φ and a length of 800 mm. Manufactured.

Next, this material was put into a pressurized extruder with a plunger set, and pressurized to suppress a tube-shaped mold with a diameter of 7.0φ and an inner diameter of 4.0φ from the mouthpiece at the tip of the extruder. After sandwiching the tube with a two-part mold, remove l from one end of the tube.
The tube material is blow-molded into a shape that follows the inner shape of the mold by blowing air into the mold as shown in Figure 4. We made 16 yuzu-shaped tubes each. This molded product was heated in air for 1 hour to about 50°C to remove organic matter.
After completely removing it, it was placed in a hydrogen atmosphere furnace and fired at 1800° C. for about 5 hours to obtain a transparent alumina tube.

The internal dimension variations and spalling strengths of these seven yuzu tubes with different shapes were as shown in the table.

Table * fIA, number of samples -1 out of 5 cases The number of occurrences is large, and the spalling intensity of Ya 2 is low due to residual running, which is considered to have good dimensional accuracy or due to the shape. Furthermore, Seed 8 does not exhibit the effects of the present invention due to large size variations. On the other hand, all of the shapes falling within the range of A4 to A70 of the present invention had small dimensional variations, high spalling strength, and had excellent characteristics as a ceramic arc tube.

As is clear from the above description, the ceramic arc tube of the present invention has a smaller external shape at the end than the central part of the tube, which is the light emitting part. In addition to being able to place the title, the official's life is long and there are 4 seeds! Since the lamp is composed of an inner wall having an angle of 60° to 90° and an inner wall facing beyond that angle, the Mi point of the lamp can be maintained more easily, so the lamp voltage and color - It is possible to suppress the variation in the value to a small value, and the present invention will contribute to the development of industry.

[Brief explanation of the drawing]

Fig. 1 is a conventional ceramic button U) simple +h+ diagram, Fig. 8 is a cross-sectional view of a ceramic arc tube showing an embodiment of the present invention. It is a sectional view of a ceramic arc tube manufactured by l...ceramic arc tube, 2... arc tube end, 3...
... Feed hole, 4... Ceramic arc tube light emitting part, 5...
・Sealing hole for electrode sealing, 6... Diameter enlarged inner surface drilling, 7...
Expanded diameter inner wall direction 11.8... Inner wall surface of the light emitting part. Applicant: Nippon Insulator Co., Ltd. Figure n Figure 3 Figure 4 (a) 0 units) ()1)

Claims (1)

[Scope of Claims] 1. A high-pressure discharge device in which the external shape of the tube end where the luminescent electrode is provided is smaller than the external shape of the central portion of the arc tube, and the Fuxiang and the central portion of the tube are made of an integral ceramic material. A ceramic arc tube for electric lamps, which has an enlarged inner groove forming an angle of 60° to 90° with respect to the axial direction of the discharge electrode from the inner end of the sealing hole of the frost electrode for exsanguination, and 1. A ceramic arc tube for a high-pressure discharge lamp, characterized in that a diameter-expanding inner curve is provided between the diameter-expanding inner curve and the luminescent inner bottle surface at the center of the tube. 2. A radius of 1 t between the enlarged diameter inner wall surface having an angle of 60° to 90° and the enlarged diameter inward direction smaller than one corner thereof.
A ceramic light emitting device 1' for a high-pressure discharge lamp according to claim 1, which has an internal groove direction parallel to the axial direction of the 1fd14.